Microscopy and Taxonomy Quiz

BIOL227 Discussion 1: Introduction to the Course

• This discussion introduces the BIOL227 course.
• The course involves laboratory studies in biodiversity.
• A wide variety of organisms from microbes to animals and plants are covered.

Lab Reports

• Complete lab reports are due before leaving the lab setting.
• Email instructor of illness to arrange alternative lab section, but this isn't always possible.
• If a lab is missed, the remaining labs and lab quiz still contribute to the final grade.
• Students are still responsible for all missed lab content in exams and quizzes.
• No make-up labs are offered.
• Plagiarism will not be tolerated.
• Copying, paraphrasing, or translating material from any external source without citing the source is unacceptable.
• Copying figures, answers, and other material from other students is prohibited.

No Electronic Devices

• Laptops, netbooks, and iPads are allowed in class but not during lab.
• No phones are allowed in lab or class.

Before Coming to Labs

• Read the lab manual.
• Watch any posted videos.
• A quiz is given at the beginning of each lab (5 minutes).
• Latecomers will receive a 0 grade.
• Bring a signed copy of the safety sheet in the first lab.

Safety Sheet

• The safety sheet is to be completed and handed in at the first lab.
• Students affirm they have read and understand the Biology Department Safety Regulations.

Course Objectives

• List unique features (organismal, cellular, subcellular) of a particular taxon.
• Label these features (cell morphology, cell walls, food/contractile vacuoles, etc.).
• Describe these features and explain their importance.
• Discuss the advantages they offer to organisms and the information they provide about an organism's environment and evolutionary history.
• Understand the diversity of organisms across taxonomic hierarchy levels.
• Identify similarities and differences amongst taxa within a taxon category.

Biodiversity

• Biodiversity represents the variety of life on Earth.
• There are three main types:
• Species diversity
• Ecosystem diversity
• Genetic diversity.
• Biodiversity is crucial for life on Earth because it helps maintain stable ecosystems and provides resources.

Biodiversity: Types

• Genetic diversity: Variations in the genetic makeup of organisms within a species. Examples include varieties of rice, wheat, maize, and barley.
• Species diversity: Different types of species residing in specific geographic areas. This is the most basic level of biodiversity.
• Ecosystem diversity: Variations in microbes, plants, and animals plus their interconnectedness through food chains and food webs. This demonstrates diversity observed in different ecosystems within a region.

Examples of Biological Diversity in the Congo River Region

• Ecosystem diversity includes swamps, the Congo river, grasslands, and rainforests.
• Species diversity in the tropical rainforests includes Myrianthus tree species that produce edible fruits, duikers (deer-like animals), African elephants, wild pigs, gorillas and lemur monkeys.
• Genetic diversity in gorillas pertains to the alleles relating to melanin production that determine hair, skin, and eye color.

Biodiversity: Microbes, Animals, Plants

• Life is organized from Domains Bacteria and Archaea (prokaryotic) to Domain Eukarya (eukaryotic) through a branching tree of life.
• Domain Eukarya includes plants, animals, fungi, and protists.
• Prokaryotes, in turn, are divided into domains Bacteria and Archaea

Biodiversity: Taxonomy

• Taxonomy is the classification and naming of organisms based on similarities and evolutionary relationships.
• The Linnaean system (Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species) categorizes organisms from broad to narrow.
• Key contributors to taxonomy include Ernst Haeckel (kingdom) and Robert Whittaker (five kingdoms).

Biodiversity: Common vs Scientific Names

• Common names are not always effective in classification.
• Scientific names (binomial nomenclature) using genus and species, are more accurate and reliable.

Biodiversity: Binomial Nomenclature

• Binomial nomenclature is a standardized two-part naming system for species.
• The first part is the genus name (capitalized) and the second is the species name (lower case).
• Both written together represents the species.
• For example, Homo sapiens

Biodiversity: Taxonomic Classification

• Taxonomists group species based on similar characteristics.
• It uses a hierarchical system: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
• This system is built from general (broad) to specific characteristics (narrow).
• A mnemonic device for these categories is "Dumb Kings Play Chess On Fine Grain Sand".

Biodiversity: Key Contributors to Taxonomy

• Early taxonomists grouped all organisms into plants or animals.
• Scientists recognized difficulties with grouping fungi, bacteria, etc with either group and began the development of kingdoms.
• Whittaker developed five kingdoms (fungi, plants, animals, protists, and monera).
• These categories later were reclassified into three domains (Bacteria, Archaea, Eukarya) and the four kingdoms in Eukarya.

Microscopy: Learning Outcomes

• Describe compound microscope parts.
• Describe light bending through condenser, objectives and ocular lenses, in media such as air, water, and oil.
• Explain how resolution improves from scanning to high-power objective lenses.
• Practice Köhler illumination, oil immersion, and dark-field illumination.

Microscopy: Branches

• Distinguish the light microscope from the electron microscope.
• Determine magnification versus resolution relation.

Microscopy: Parts

• Diagram and descriptions are provided for each part of a compound microscope (eyepieces, diopter adjustment ring, revolving nosepiece, specimen holder, transport lock pin, aperture iris diaphragm knob, condenser centering screws, condenser, filter holder, and field diaphragm ring).

Microscopy: Lenses

• Three main lenses (condenser, objective, ocular).
• The condenser lens focuses light onto the specimen to improve image clarity.

Microscopy: Refractive Index

• Light changes speed and direction when moving between media with different densities (refraction).
• The refractive index of a medium measures how much slower light travels compared to its velocity in a vacuum. Air=1, Glass=1.52, Oil=1.52

Microscopy: Resolution

• Resolution is the ability of a lens to distinguish close objects.
• Abbe's equation relates resolution to the wavelength of light, refractive index, and the angle of light entering the lens.

Microscopy: Köhler Illumination

• The Köhler illumination method provides even illumination across the entire specimen field.
• This method enhances image contrast and resolution by correctly centering the light cone from the condenser.